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Developing black and white for scanning

Over the weekend I went to order some more of my favourite developer Paterson Aculux 3 only to find that Paterson chemicals have been discontinued. Whether they will emerge again in another guise remains to be seen but it is particularly frustrating as I had built my darkroom processes and timings around Aculux 3 and I was particularly partial its beautiful tonality.

As I need to start again finding a new developer and re-test for my films, I thought I would share a few thoughts on a less risky strategy (in terms of making the wrong bet again) and also share the main conclusions from my exploration of modern dark room practices a few years ago

Hindsight is a wonderful thing but now I look at it, Aculux 3 had two major drawbacks. Firstly it is distributed in liquid form. This was a big advantage for me in that I didn't have to mix from powders (which worries me given my Ashma). The problem is that the cost of manufacture and distribution must be substantially higher than powered chemicals. Also the shelf life is substantially shorter. This makes it much more likely that the last chemicals distributed will be in powered form. And easier to stock up on for a long time by bulk buying.

Secondly, it is a proprietary formula. This makes it difficult for small providers to replicate the product under niche manufacture unless the formula is published. However there are a whole host of developers for which the formulae are published - from that Kodak/Ilford standard D76/ID-11 (basically the same developer with only minor differences) to staining developers like Pyrochat-HD.

The age of the specialist proprietary developer (with hidden magical properties) is gone. And arguably is not necessary any more, given that 35mm film is looking increasingly obsolete. Many of the proprietary developers were designed to try and give 35mm negatives with insufficient real estate a bit more of an edge in terms of sharpness or grain when enlarged. Larger formats (10x8, 5x4 and arguably 120mm) just don't need this. For example Ansel Adams used a very simple developer D76 pretty extensively with his large format work.

So a powdered, published formula it will be, probably from Ilford which will give me the most confidence in longevity. Nice tonality and consistency will be the deciding factors.

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Several years ago I got to grips with black and white development and rather found I liked it - it gave me an immediate connection and feeling for my work that sending images off to a lab could not replicate. And a level of control over the result which was very satisfying.

Here are a few of my conclusions:

1. Developing to scan is completely different to developing to wet print. The kind of negative that works best for scanning is exactly the kind of negative that was traditionally difficult to print - namely a thin negative. Under developing is the key to a successful hybrid process. It avoids too many dense patches in the negative (prone to more grain which is exaggerated in a scan and being much harder to scan with a scanner with limited dmax such as an Epson v700/750. )

Contrast is easy to add back in with a curve or two in Photoshop preserving nice tonality. Working in reverse (say reducing contrast from a normally developed negative or a n+1 negative) seems to damage the quality of mid tones.

In short, reducing development times by 20-30 % and rating the film a little lower than published (e.g. A 125 EI film rated at say 64-80) is the way to go.

2. So the zone system is unnecessary then? Well no, in fact it is still valid. The principles still apply and are useful, it is just that the level of precision that it was solving for is not really necessary. Let me explain. The zone system was created to allow 10 distinct tones (called zones) from white to black to be translated precisely from the scene through the negative to a particular grade of paper. It allowed photographers to realise their vision in a final print and it was essential to get consistent predictable results. Scanning and printing digitally gives us much more fine control of the print almost regardless of the negative. So the level of precision demanded by the zone system is not really necessary any more unless you intend to wet print. However the following key principles fundamental to the zone system still apply and are still essential to get good results...

3. You need to know where to place the shadow detail - ideally on zone 3 or two stops below the mid point. The reason for this is once exposed it is possible to recover highlight detail by changing the development time but it is not possible to recover shadow detail. In fact the shadow area around zone 2/3 hardly moves at all in response to different development times.

The classic way to do this was to test for the EI of the film by fixing the normal development time and measuring the density of shadow tones for a series of images shot at different EIs. There are plenty of instructions on the web for how to do this and knowing the actual EI of your film for the normal developing time for your process (film, developer, dilution, developing technique) is very very useful. However it is also possible by trial and error to get close enough - just meter the shadows two stops down and increase exposure (reduce EI) if you keep losing shadow detail.

As an aside, the box speeds of most films are optimistically fast and correspondingly the standard development times are probably too long. It is a hang over from the consumer age of film where the promise of a slightly faster film or a film that could be 'pushed' faster was essential to make the product competitive.

4. Contrast control through changing the development time is still very useful. Basically increase the development time by 20% to increase contrast by one stop (n+1). Reduce development time by 20% to reduce contrast by one stop (n-1). In practice this adjustment differs by film / developer / process but it is approximately right and again in the world of scanning this is likely to be good enough. Hence the advice in step 1 above to under develop by 20-30% is basically saying make your default negative a n-1 negative under the zone system. Through extensive testing (or a bit of trial and error it is up to you!) you can work out exactly where the highlights will fall on a n-1 developed negative and you can be sure you have captured all the detail you need. Consistency is the key - pick a base development time and EI (for a film/developer combination) and stick to it for your normal development time. Make a plan to adjust development when you actually make the image - and only if necessary based on the dynamic range of the scene - usually reducing the development time (lowering the contrast) for higher dynamic range images.

5. Extreme contrast scenes that don't fit within the dynamic range of your 'normal for scanning' development times can still be handled using a little known and frequently misunderstood technique championed very quietly by Adams in 'The Negative' - the two bath technique. This traditional large format technique was adapted by the two bath developer movement in the 70s and 80s seeking to create a 2 part developer where very little development was done in the first bath. The aim was a compensating effect where the highlights exhaust the developer but he shadows continued to develop - effectively increasing the dynamic range of the film and promising to dynamically alter the contrast levels between the frames on a roll.

The Adams technique is much much simpler and does not call for anything other than a standard developer and a packet of borax! The idea is to develop the highlights in the developer until just before they are fully developed. Typically this might be 50% of normal development time in a high contrast scene. Then transfer the negative to a second bath of borax solution (2 heaped tsp per 1l) and stand the negative in this (no agitation - this is important) for 4 minutes. The aim is to fully develop the shadows at this point, exhausting the developer in the highlights. Then proceed as normal.

As an aside I have had very good and consistent results with this technique, unlike the other so called compensation based techniques of diluted developers and stand/reduced agitation. I have found these techniques very unreliable with intermittent streaking of the negatives and uneven development. The above technique has little or no risk of uneven development precisely because the first bath develops the negative (unlike the no development in the first bath 'two bath' techniques that similarly suffered from some intermittent uneven development).

The only thing to watch for with this 2 bath approach is to make sure the development time in the developer is sufficient to get an even result. E.g. If the development time is < 3-4 minutes it might be better to dilute the developer to get an extended development time.

Finally, an FYI: For 5x4 and 10x8 I use continuous agitation in a converted Paterson orbital (fins cut off - again a quick search on the Internet will show you the details). A jobo would be fine too (I have one but am saving it for the days when I need it for colour transparency!) but the orbital is very simple and easy.

So there it is - developing negatives to scan. In a nutshell:
1. Meter for the shadow detail at 2 stops below and adjust the speed you rate the film until you consistently record shadow details in your negatives - don't stay on box speed
2. Under develop - typically at least 20-30% below standard published development times or n-1 in old zone system money
3. If you need an extreme contrast range, try Ansel's two bath trick

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